Creating an array of buttons using "for loop" and using the value inside to change a bool-array value

Question

(Updated) Sorry if this is getting more and more like a guide. Is there any other site I should post this on?

I'm making a yatzy game and I'm on my way learning for loops. My method is similar to the top answer's in this question: dynamic button onclick event inside for loop Here's my code: (Yes I'm mixing languages, I'm sorry)

package se.balderskolan.yatzy;

    import java.util.Random;
    import android.os.Bundle;
    import android.app.Activity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.ImageButton;

    public class MainActivity extends Activity {

Button btKasta;
Random r = new Random();
int[] tarningar = new int[5];
int[] bilder = new int [6];
ImageButton [] img= new ImageButton[5];
boolean [] bool = new boolean[5];

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    btKasta = (Button)findViewById(R.id.btKasta);

    bilder [0]=R.drawable.b1; //Pictures of the dices
    bilder [1]=R.drawable.b2;
    bilder [2]=R.drawable.b3;
    bilder [3]=R.drawable.b4;
    bilder [4]=R.drawable.b5;
    bilder [5]=R.drawable.b6;

    img [0] = (ImageButton)findViewById(R.id.imgbt1); //The grafical dices
    img [1] = (ImageButton)findViewById(R.id.imgbt2);
    img [2] = (ImageButton)findViewById(R.id.imgbt3);
    img [3] = (ImageButton)findViewById(R.id.imgbt4);
    img [4] = (ImageButton)findViewById(R.id.imgbt5);


    //The die-buttons (save or not)
    img [0].setOnClickListener(
            new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    if(bool [0] == false) {
                        bool [0] = true;
                    }

                    else{
                        bool [0] = false;
                    }
                }
            }
            );

    img [1].setOnClickListener(
            new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    if(bool [1] == false) {
                        bool [1] = true;
                    }

                    else{
                        bool [1] = false;
                    }
                }
            }
            );

    img [2].setOnClickListener(
            new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    if(bool [2] == false) {
                        bool [2] = true;
                    }

                    else{
                        bool [2] = false;
                    }
                }
            }
            );

    img [3].setOnClickListener(
            new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    if(bool [3] == false) {
                        bool [3] = true;
                    }

                    else{
                        bool [3] = false;
                    }
                }
            }
            );

    img [4].setOnClickListener(
            new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    if(bool [4] == false) {
                        bool [4] = true;
                    }

                    else{
                        bool [4] = false;
                    }
                }
            }
            );

    /*I want to replace the code above with something like this below

    for(imgbt=0; imgbt<5; imgbt++){
        img [imgbt].setOnClickListener(
                new View.OnClickListener() {

                    @Override
                    public void onClick(View v) {

                        if(bool [imgbt] == false) {
                            bool [imgbt] = true;
                        }
                        else{
                            bool [imgbt] = false;
                        }

                    }
                }
        );

    }
    */

  //The die-throwing button
    btKasta.setOnClickListener(             
        new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                    for(int i=0; i<5; i++){
                        tarningar [i]=r.nextInt(6);

                        if (bool[i]==false){
                            img [i].setImageResource(bilder [tarningar[i]]);}
                        else{}
                    }                   
                }
            }
    );
}

    }

(I can add that I have succesfully had the bottons save dices using the code without the for-loop.)

After doing some research in my code I discovered the following about the button-for-loop:

The value of "imgbt" is 5 at row
```
if(bool [imgbt] == false)
```
Which gives me the "ArrayIndexOutOfBoundsException"-error.
All of the buttons always changes the bool-value of bool [5] (Which doesn't exist. I found this by increasing the nuber of arrays created up in the declaration)

If I declare

    int imgbt = 0

inside the for-loop eclipse gives me the error:

    Cannot refer to a non-final variable imgbt inside an inner class defined in a different method

(Can someone explain this error?)

So do you know any solution to my problem, or another way to work around it, please do not hesitate to awnser!

Nikolay Elenkov · Accepted Answer · 2012-10-17 08:26:56Z

2

This doesn't really have much to do with Android, it's basic Java. In short:

arrays start from index 0
an object array (such as Boolean) is by default initialized with nulls
you need to make the two arrays the same size

So,

start your loop from 0
use booolean[] instead of Boolean[] or initialize it with Boolean.FALSE before use`
make both arrays size 6

answered Oct 17, 2012 at 8:26

Nikolay Elenkov

53k12 gold badges86 silver badges84 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Epcilon Over a year ago

Thanks for your help! I learned a bit from it. Despite that my problem is not yet fixed.

Nikolay Elenkov Over a year ago

This is getting tutorial-like, so SO might not be the best place. Spend some more time with your Java book and learn how to use the debugger to see where the problem is. And maybe show all of your code, so people don't have to guess. BTW, the canonical way to write a for loop for arrays is: for (int i = 0; i < array.length; i++) { array[i] = foo;}

Epcilon Over a year ago

I'm not sure I understood how you ment I should write a for loop.

Rovanion · Accepted Answer · 2012-10-26 20:32:42Z

1

So your real problem was that you were using a mutable, non-final, variable when defining an override in a class. So if you modify the code to look like the fallowing:

for(imgbt=0; imgbt<5; imgbt++){
    public final someInteger = imgbt;
    img [imgbt].setOnClickListener(
           new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(bool [someInteger] == false) {
                        bool [someInteger] = true;
                    }
                    else{
                        bool [someInteger] = false;
                    }
              }
         }
    );
}

It should work out just fine.

answered Oct 26, 2012 at 20:32

Rovanion

4,6463 gold badges32 silver badges54 bronze badges

Comments

ariefbayu · Accepted Answer · 2012-10-17 08:25:00Z

0

You need to instantiate the array, like this:

Boolean bool[] = new Boolean[]{false, false, false, false, false, false, false};

answered Oct 17, 2012 at 8:25

ariefbayu

22k13 gold badges73 silver badges93 bronze badges

Collectives™ on Stack Overflow

Creating an array of buttons using "for loop" and using the value inside to change a bool-array value

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related